For some reason, it has been really difficult getting some video footage of the 3DS.
Maybe it's because cameras weren't allowed on the show floor, or they just didn't bother since you won't be able to see the 3D. But someone bothered/got away with it, and we got some badly shot video footage of Paper Mario 3DS (and some bit of beta Mario Kart 3DS).
Seems like they are going to push the contrast between the 2D characters and the 3D world this time, which should be very interesting visually, and of course, it's a whole new game, so it should be awesome. Mario Kart 3DS ain't worth talking about much, since it probably won't come out for another 2 or 3 years, and the tiny tech demo was not playable and used assets from previous games (except the music).